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Credit:
The information has been provided by Fernando Arnaboldi and Jos Orlicki .
The original article can be found at: http://corelabs.coresecurity.com/index.php?action=view&type=advisory&name=WordPress_Privileges_Unchecked
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Vulnerable Systems:
* WordPress version 2.8 and prior
* WordPress MU version 2.7.1 and prior
Immune Systems:
* WordPress version 2.8.1
* WordPress MU version 2.8.1 and prior
Arbitrary native code may be run by a malicious attacker if the blog administrator runs injected JavasScript code that edits blog PHP code. Many WordPress-powered blogs, hosted outside 'wordpress.com', allow any person to create unprivileged users called subscribers. Other sensitive username information disclosures were found in WordPress.
Workaround:
Mitigation for the Privileges Unchecked vulnerability: this vulnerability may be mitigated by controlling access to files inside the 'wp-admin' folder. Access can be prohibited by using Apache access control mechanism ('.htaccess' file), see guideline for more information.
In the last few years several security bugs were found in WordPress. During 2008, the big amount of bugs reported by researchers lead to exploitation by blog spammers. During 2009, a new round of attacks has appeared and security researchers are reporting new bugs or wrongly fixed previously-reported bugs. A path traversal in local files included by 'admin.php' has been fixed but, in our case, we report that administrative privileges are still unchecked when accessing any PHP file inside a plugin folder.
Access Control Roles
WordPress has a privilege model where any user has an assigned role.
Regarding plugins only users characterized by the role Administrator can activate plugins. Notice that only the blog hosting owner can add new plugins because these must by copied inside the host filesystem. The roles Editor, Author or Subscriber (the latter has the least privileges) cannot activate plugins, edit plugins, update plugins nor delete plugins installed by an Administrator. Besides that, the configuration of specific plugins is a grey area because there is no distinguished capability assigned.
Also due to cross-site scripting vulnerabilities inside plugins options (something very common), non-administrative users reconfiguring plugins may inject persistent JavaScript code. Possibly arbitrary native code can be executed by the attacker if the blog administrator runs injected JavasScript code that injects PHP code. It is important to observe that many WordPress-powered blogs are configured to allow any blog visitor to create a Subscriber user without confirmation from the Administrator role inside the following URL, although by default the Administrator role must create these new users.
http://[some_wordpress_blog]/wp-login.php?action=register
This can be modified by the administrator in 'Membership/Anyone can register'.
http://[some_wordpress_blog]/wp-admin/options-general.php
Privileges Unchecked in admin.php?page= Plugin Local File Includes (CVE-2009-2334)
No privileges are checked on WordPress plugins configuration PHP modules using parameter 'page' when we replace 'options-general.php' with 'admin.php'. The same thing happens when replacing other modules such as 'plugins.php' with 'admin.php'. Basic information disclosure is done this way. For example, with the following URL a user with no privileges can see the configuration of plugin Collapsing Archives, if installed.
http://[some_wordpress_blog]/wp-admin/admin.php?page=/collapsing-archives/options.txt
Instead of the following allowed URL.
http://[some_wordpress_blog]/wp-admin/options-general.php?page=collapsing-archives/options.txt
Another example of this information disclosure is shown on Akismet, a plugin shipped by default with WordPress.
http://[some_wordpress_blog]/wp-admin/admin.php?page=akismet/readme.txt
All plugins we have tested are vulnerable to this kind of information disclosure, but in many of them the PHP files accessed just crashed. On the other hand, for example, with capability 'import', privileges are checked inside 'admin.php':
if ( ! current_user_can('import') )
wp_die(__('You are not allowed to import.'));
More dangerous scenarios exist, all of them can be exploited by users with the Subscriber role, the least privileged.
Abuse example: XSS in plugin configuration module
If installed, *Related Ways To Take Action* is an example of a WordPress plugin that is affected by many cross-site scripting vulnerabilities (XSS) that can be leveraged by an attacker using the unchecked privileges described in this advisory to inject persistent JavaScript code. Possibly, arbitrary native code can be executed by the attacker if the blog administrator, when he/she logs in, runs injected JavasScript code that edits blog PHP code. The original URL for reconfiguring the plugin can be accessed only by the Administrator role.
http://[some_wordpress_blog]/wordpress/wp-admin/options-general.php?page=related-ways-to-take-action/options.php
But replacing the PHP file with the generic 'admin.php' any blog user can modify this configuration.
http://[some_wordpress_blog]/wp-admin/admin.php?page=related-ways-to-take-action/options.php
The following JavaScript injection can be entered within field *Exclude actions by term* to exemplify this kind of abuse. When the administrator enters the same page the injected browser code will be executed and possibly blog PHP can be modified to run arbitrary native code.
\"/><script>alert(String.fromCharCode(88)+String.fromCharCode(83)+String.fromCharCode(83))</script><ahref="
This is the worst scenario that we found for the vulnerability.
Abuse example: viewing WP Security Scanner Plugin Dashboard
If installed, the WordPress Security Scanner Plugin dashboard can be viewed similarly by any user besides the administrator using the plugin configuration page URL without modification. This dashboard includes common default blog configuration settings that are insecure and should be modified by the blog administrator or hosting.
http://[some_wordpress_blog]/wp-admin/admin.php?page=wp-security-scan/securityscan.php
Abuse example: reconfiguring WP-IDS, a WordPress Hardening Project
If installed, the *Intrusion Detection System Plugin (WPIDS)*[10] can be reconfigured accessed with the same vulnerability.
http://[some_wordpress_blog]/wp-admin/index.php?page=wp-ids/ids-admin.php
This gives an attacker the possibility to disable many features of the plugin, for example reactivate the forgotten password feature and reactivate the XML-RPC blog interface. Also you can deny the weblog service by configuring this plugin to be overly sensitive, blocking any request. However the plugin cannot be totally disabled because the essential IDS parameters 'Maximum impact to ignore bad requests' and 'Minimum impact to sanitize bad requests' are verified on the server side of the blog and cannot be distorted to deactivate the sanitizing or blocking features of the web IDS plugin.
Other Information Disclosures (CVE-2009-2335, CVE-2009-2336)
WordPress discriminates bad password from bad user logins, this reduces the complexity of a brute force attack on WordPress blogs login (CVE-2009-2335, BID 35584). The same user information disclosure happens when users use the forgotten mail interface to request a new password (CVE-2009-2336, same BID 35584). These information disclosures seem to be previously reported but the WordPress team is refusing to modify them alleging *user convenience*.
Default installation of WordPress 2.7.1 leaks the name of the user posting entries inside the HTML of the blog.
<small>June 3rd, 2009 <!-- by leakedusername --></small>
Also several administrative modules give to anyone the complete path where the web application is hosted inside the server. This may simplify or enable other malicious attacks. An example follows.
http://[some_wordpress_blog]/wp-settings.php
Notice: Use of undefined constant ABSPATH - assumed 'ABSPATH' in [WP_LEAKED_PATH]\wp-settings.php on line 110
Notice: Use of undefined constant ABSPATH - assumed 'ABSPATH' in [WP_LEAKED_PATH]\wp-settings.php on line 112
Warning: require(ABSPATHwp-includes/compat.php) [function.require]:
failed to open stream:
No such file or directory in [WP_LEAKED_PATH]\wp-settings.php on line 246 Fatal error: require() [function.require]: Failed opening required 'ABSPATHwp-includes/compat.php'
(include_path='.;[PHP_LEAKED_PATH]\php5\pear') in [WP_LEAKED_PATH]\wp-settings.php on line 246
CVE Information:
CVE-2009-2334
CVE-2009-2335
CVE-2009-2336
Disclosure Timeline:
.2009-06-04: Core Security Technologies notifies the WordPress team of the vulnerabilities (security@wordpress.org) and offers a technical description encrypted or in plain-text. Advisory is planned for publication on June 22th.
2009-06-08: Core notifies again the WordPress team of the vulnerability.
2009-06-10: The WordPress team asks Core for a technical description of the vulnerability in plain-text.
2009-06-11: Technical details sent to WordPress team by Core.
2009-06-11: WordPress team notifies Core that a fix was produced and is available to Core for testing. WordPress team asserts that password and username discrimination as well as username leakage are known and will not be fixed because they are convenient for the users.
2009-06-12: Core tells the WordPress team that the patch will be tested by Core as a courtesy as soon as possible. It also requests confirmation that WordPress versions 2.8 and earlier, and WordPress.com, are vulnerable to the flaws included in the advisory draft CORE-2009-0515.
2009-06-12: WordPress team confirms that WordPress 2.8 and earlier plus WordPress.com are vulnerable to the flaws included in the advisory draft.
2009-06-17: Core informs the WordPress team that the patch is only fixing one of the four proof of concept abuses included in the advisory draft. Core reminds the WordPress team that the advisory is scheduled to be published on June 22th but a new schedule can be discussed.
2009-06-19: Core asks for a new patched version of WordPress, if available, and notifies the WordPress team that the publication of the advisory was re-scheduled to June 30th.
2009-06-19: WordPress team confirms they have a new patch that has the potential to break a lot of plugins.
2009-06-29: WordPress team asks for a delayance on advisory CORE-2009-0515 publication until July 6th, when WordPress MU version will be patched.
2009-06-29: Core agrees to delay publication of advisory CORE-2009-0515 until July 6th.
2009-06-29: Core tells the WordPress team that other administrative PHP modules can also be rendered by non-administrative users, such as module 'admin-post.php' and 'link-parse-opml.php'.
2009-07-02: WordPress team comments that 'admin.php' and 'admin-post.php' are intentionally open and plugins can choose to hook either privileged or unprivileged actions. They also comment that unprivileged access to 'link-parse-opml.php' is benign but having this file open is bad form.
2009-07-02: Core sends the WordPress team a new draft of the advisory and comments that there is no capability specified in Worpress documentation for configuring plugins. Also control of actions registered by plugins is not enforced. Core also notices that the privileges unchecked bug in 'admin.php?page=' is fixed on WordPress 2.8.1-beta2 latest development release.
2009-07-06: Core requests WordPress confirmation of the release date of WordPress
2.8.1 and WordPress MU 2.8.
2009-07-07: WordPress team confirms that a release candidate of WordPress 2.8.1 is made available to users and that the advisory may be published.
2009-07-06: Core requests WordPress confirmation of the release date of WordPress MU and WordPress MU new version numbers.
2009-07-07: WordPress team release WordPress 2.8.1 RC1 to its users.
2009-07-08: WordPress team confirms that WordPress MU 2.8.1 will be made available as soon WordPress 2.8.1 is officially released. Probably July 8th or 9th.
2009-07-08: The advisory CORE-2009-0515 is published.
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